Abstract
For the X-ray stress measurement in the region which has a steep stress gradient such as the neighborhood of a crack, a smaller irradiation area is required to estimate highly precise stresses. However, the reduction of the irradiated area brings a decrease in diffraction intensity and spotty diffraction pattern. In the conventional X-ray stress measurement using a scintillation counter, 1000 grains within the irradiated area and the oscillation method are recommended. However, for the sin2ψ method using a two-dimensional detector, effect of measurement conditions is not clear yet. In the present study, the effects of the oscillation condition and irradiated area on the accuracy of the stress measured by the sin2ψ method were investigated. For the oscillation effect, θ angle was more effective than χ angle. For the two-dimensional detector, the decrement of the number of grains required for accurate stress determination corresponded to the increase of the area of the detector. The stress distribution near a crack was able to be measured with the collimator diameter of 0.3 mm or more with enough accuracy for 2024-T3. It was suggested that actual stress could be evaluated by the reverse analysis of measured average stresses.
